scanner is a fast non-backtracking incremental combinator parsing
library for bytestrings.
It is often convenient to use backtracking to parse some sophisticated
input. Unfortunately it kills performance, so usually you should
avoid backtracking.
Often (actually always, but it could be too hard sometimes) you can
implement your parser without any backtracking. It that case all
the bookkeeping usual parser combinators do becomes unnecessary.
The scanner library is designed for such cases. It is often 2 times
faster than attoparsec.
